Observation on Baseline Sensitivity of &amp;lt;i&amp;gt;Erysiphe necator&amp;lt;/i&amp;gt; Genetic Groups to Azoxystrobin

Hajjeh, Hajaj

doi:10.4236/ajps.2012.311199

Cited by 3 publications

(2 citation statements)

References 16 publications

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“…Another hypothesis for disappearance of group A during later stages is that group B isolates are less sensitive to demethylation inhibitor fungicides and quinone outside inhibitor fungicides as compared to group A isolates, such that the fungicide selection pressure during later stages may have favored group B over group A (Miazzi and Hajjeh 2011;Hajjeh 2012;Dufour et al 2011). This idea is supported by the observation that group A isolates can be found throughout the season in vineyards that are not treated with fungicides (Montarry et al 2009).…”

Section: Introductionmentioning

confidence: 98%

Genetic variation and survival of Erysiphe necator in tropical India

Ghule

Sawant

et al. 2019

Trop. plant pathol.

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The heterothallic, biotrophic fungus Erysiphe necator causes powdery mildew on grapes which impacts the yield and quality of fruits and their processed products. Two genetic groups, A and B, have been described which overwinter either as flag shoots or chasmothecia. The genetic structure of the Indian isolates and their oversummering mode in tropical regions is not known. In this study, population genetic analysis of 26 and 134 E. necator isolates from temperate and tropical regions of India, respectively, was performed. PCR analysis showed presence of both genetic groups A and B in temperate regions and only genetic group B in tropical regions. Flag shoots were not observed in tropical region. Weather data analysis and temperature sensitivity of E. necator conidia indicate the possibility of the pathogen oversummering as conidia on bark. Sequence analysis of ITS (Internal Transcribed Spacer), IGS (Intergenic Spacer), TUB2 (Beta-Tubulin) and EF1-α (Translation Elongation Factor 1-α) genes covering 1762 nucleotides from 22 isolates showed the presence of four haplotypes, A-IN1, B-IN1, B-IN2 and B-IN3 in temperate regions and only haplotype B-IN3 in tropical regions. Haplotypes A-IN1 and B-IN1 were similar to haplotypes of group A and B, respectively, reported from USA, Europe and Australia. The other two haplotypes, B-IN2 and B-IN3 grouped with haplotypes from USA and are new reports from India. The diversity and haplotype structure suggest that powdery mildew was introduced in north India and then moved to tropical regions corroborating historical reports of the introduction of grapevines in India. Occurrence of a genetic group with lower fungicide sensitivity and greater aggressiveness might explain the difficulties to manage this disease in Maharashtra, India.

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Section: Introductionmentioning

confidence: 98%

Genetic variation and survival of Erysiphe necator in tropical India

Ghule

Sawant

et al. 2019

Trop. plant pathol.

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“…The "ascospore" biotype is more frequently associated to later infections on bunches and leaves. In addition to that resent studies shows that the "flag shoot" derived isolates is more sensitive, to certain types of systemic fungicides, than "ascospore" derived isolates, which favors "ascospore" biotype over the other affecting the evolution of the epidemics (Miazzi and Hajjeh 2011;Hajjeh, 2012).…”

Section: Discussionmentioning

confidence: 99%

Role of Overwintering Forms of Erysiphe necator in Epidemiology of Grapevine Powdery Mildew in Palestinian Vineyards

Abuamsha¹,

Hajjeh²,

Salman³

2014

PTUKRJ

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The overwintering modes of E. necator were studied on Palestinian vineyards, through observations on the differentiation and maturation of cleistothecia and on the occurrence of flag-shoots (deriving from overwintering mycelium) in vineyards. Field surveys were carried out in 17 vineyards for the presence of Flag shoots and cleistothecia, both forms were not observed. Genetic structure and composition of E. necator populations were investigated by application of already available SCAR (Sequence Characterized Amplified Region) primers specific for the "flag-shoot" and "ascospore" biotypes. These primers were used to evaluate the dynamics of the spatial and temporal distribution of the two biotypes, into fungal populations present in 8 vineyards, with different cultivars and spray histories, in various Palestinian districts (Hebron, Bethlehem, Jerusalem, Ramallah, Jericho, Nablus, Jenin, Tulkarm). 397 samples were analyzed by the uses of the primer pairs UnE-UnF in PCR reactions. All samples were found to be of the ascospore biotypes. This finding shows that the “flag shoot” biotype, appears soon after bud breaking and disappears later, while the “ascospore” biotype is more frequently associated to later infections and bunches damages. Such information would be helpful to understand the reasons underlying possible temporal evolution of the pathogen's populations in vineyards, and can have important implications for powdery mildew rationale control strategies.

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Grapevine Powdery Mildew: Fungicides for Its Management and Advances in Molecular Detection of Markers Associated with Resistance

et al. 2021

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Grapevine powdery mildew is a principal fungal disease of grapevine worldwide. Even though it usually does not cause plant death directly, heavy infections can lead to extensive yield losses, and even low levels of the disease can negatively affect the quality of the wine. Therefore, intensive spraying programs are commonly applied to control the disease, which often leads to the emergence and spread of powdery mildew strains resistant to different fungicides. In this review, we describe major fungicide classes used for grapevine powdery mildew management and the most common single nucleotide mutations in target genes known to confer resistance to different classes of fungicides. We searched the current literature to review the development of novel molecular methods for quick detection and monitoring of resistance to commonly used single-site fungicides against Erysiphe necator. We analyze and compare the developed methods. From our investigation it became evident that this research topic has been strongly neglected and we hope that effective molecular methods will be developed also for resistance monitoring in biotroph pathogens.

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Observation on Baseline Sensitivity of <i>Erysiphe necator</i> Genetic Groups to Azoxystrobin

Cited by 3 publications

References 16 publications

Genetic variation and survival of Erysiphe necator in tropical India

Genetic variation and survival of Erysiphe necator in tropical India

Role of Overwintering Forms of Erysiphe necator in Epidemiology of Grapevine Powdery Mildew in Palestinian Vineyards

Grapevine Powdery Mildew: Fungicides for Its Management and Advances in Molecular Detection of Markers Associated with Resistance

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